First possible indication of a 2^nd form of primordial matter

Budapest, May 22, 2026. – Results prepared by a group of Hungarian researchers, supported by the Research Excellence Program of MATE University, headed by Tamás Csörgő, a physicist, member of Academia Europaea, were published as Editors' Suggestion in the Physical Review C, the leading nuclear physics journal of the American Physical Society. This indirect, quantum nuclear physics result may provide the first glimpse at the 2^nd new form of primordial matter that once filled the early Universe.

A poem by T. D. Lee, a Chinese-American Nobel laureate in physics inspired a famous painting (Figure 1) by Li Keran, one of the most important Chinese artists of the 20th century. This 1989 poetic painting of two horn-locked heavy bulls in collision became an allegory for heavy ion collisions. T. D. Lee's poem reads in English translation as follows:

This poem by T. D. Lee is ingenious from several points of view: it is not only a powerful poem of a picture and a powerful picture of a poem, but it is a powerful prophecy in physics as well. T.D. Lee's lines phrase transitions and the generation of new states of matter. In 1989, it forecasted not only a single kind of a new state of matter, but at least two new states of matter. In this sense, this poem connects to the new experimental results obtained by Hungarian researchers for the PHENIX Collaboration. The poem is based on a scientific conjecture of T.D. Lee and G. C. Wick, published more than 50 years ago, in 1974, in Physical Review D, the leading particle physics journal of the American Physical Society. According to the conjectured physical picture, the empty space, the so-called vacuum actually more resembles a medium whose properties can be changed. Thus empty space has properties, for example, it has a temperature. For a medium, consider water as an example. Water has a temperature. In winter time, below the freezing point, water freezes to ice. When put on fire, and its temperature increases above the boiling point, water turns to steam.

The 1974 prediction of G. C. Wick and T. D. Lee has been extended in 1975 by S. Weinberg, a Nobel laureate in physics and updated in 1984, based on QCD, the theory of the strong interactions, by two American physicists, R. Pisarski and F. Wilczek, a Nobel laureate in physics. According to their theory, at extremely high temperatures a kind of chiral symmetry, similar to the symmetry between the left and right hands, may be restored. As a specific kind of chiral symmetry restoration, the mass of one of the particles, that of the so called η' meson, may possibly be reduced in a color-white, hot hadronic matter. The mass of the modified η'* meson may not only be similar to that of its particle-twin, the mass of the η meson, but also to the mass of other members of its particle family in a color-white, hot hadronic matter at about 2 000 000 000 000 Celsius or 2 Tera °C. At even higher temperatures, at about 4 Tera °C, the color-white hot hadronic matter may melt further and a colorful, nearly perfect fluid of quarks may be created. The RHIC proposal from 1984 planned for the observation of at least two kind of new states of matter. The perfect liquid of quarks, known also as the colorful quark-gluon plasma, became the first form of primordial matter, that once filled the early Universe.

Hungarian physicists, analyzing the data of the PHENIX experiment, lead by researchers from the MATE University, including the researchers from Debrecen University, Eötvös University, HUN-REN ATOMKI and HUN-REN Wigner Research Centre for Physics, in a big international collaboration, could now have the first possible glimpse at a second form of the primordial matter, that once filled the whole Universe, according to the nearly 50 years old predictions of T. D. Lee and S. Weinberg, Nobel laureates in physics, and the 40 years old prediction of F. Wilczek, Nobel laureate in physics. Although PHENIX data are not inconsistent with this phenomenon, however, alternative explanations are in principle also possible due to the indirect nature of the method of observation.

„Color deconfinement and chiral-symmetry restoration have long been predicted by QCD theory. Color deconfinement in the form of a nearly perfect fluid of quarks was reported by all four RHIC experiments in 2005. Now, the PHENIX Collaboration details two-pion Lévy-stable Bose-Einstein correlation data in Au+Au collisions at the top RHIC energy. They report a significant reduction of the mass of the η′ meson in hot and dense hadronic, color-confining matter. This implies a second transition in QCD by the return of the so-called prodigal Goldstone boson—a specific kind of partial chiral-symmetry restoration—and calls for further, challenging experimental studies, aiming at direct measurements of identified η′ spectra in high-energy heavy-ion collisions". – suggested the editors of the Physical Review C.

On April 3, 2026 an alternative analysis has been published in the European Physical Journal C, by the leadership of Máté Csanád (Eötvös Loránd University, Budapest, Hungary). In this work, researchers at the Eötvös Loránd University observed, that one of the important data measured by the PHENIX experiment, the so-called correlation strength or λ parameter can also be described without in-medium mass modification of the η' meson, using the so-called EPOS model simulations. However, the other parameters of the PHENIX correlation measurements cannot be described within the same EPOS model study. Thus further investigations are necessary to explore the possible reasons of the PHENIX measurements and to clarify its possible alternative explanations.

The validity of the scientific content of this press release in Hungarian original, and its English translation is the responsibility of

Csörgő, Tamás, member of Academia Europaea
(Principal Investigator of MATE Femtoscopy Research Excellence Group)
MATE Institute of Technology, Femtoscopy Lab, Gyöngyös,
and HUN-REN Wigner RCP, Budapest, Hungary)

and

Csanád, Máté, member of Academia Europaea
(acting director, Institute for Physics and Astronomy of Eötvös Loránd University,
Department of Atomic Physics, Budapest, Hungary)